Top End Miss

Just tossing out an idea. Sounds like you've replaced/checked a lot of items. Spark plug wires with a high resistance open will cause missing at higher RPMs. A while back I put in new 8mm SPWires (well known supposedly top of the line wires) and developed a miss at higher RPMs. I took them back within hours of buying them and the parts dealer told me these wires are the best and didn't want to give me new ones. I bought some Taylor's and put them in and the miss was gone, he then gave me my money back for the other wires.